Hydraulic pump or motor



r Mrch 22, `1938. E. K: BENEDEK HYDRAULIC PUMP 0R MOTOR Filed Oc't. 24, 1934 6 sheets-sheet 1v LEKKEEND Mmh 22, 1938. A

` E. K. BENEDEK Filed oct. Q4, 19:54

' 3m@ L-EK KENED mi T151 mi;

March 2,2, 1938. A

E. K. BENEDEK HYDRAULIC PUMPQR MOTOR Filed Oct. 24,- 1934 e sheets-sheet 5 EKKEENEDEK March 22, 1938. E. K. BENEDEK HYDRAULIC FUME OR MOTOR Filed oc't. 24, 1934 6 Sheets-Sheet'' Y, hl W una@ .wmf

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Immo/toas ,N JLEKKEENEDEK Q a UNITED sTMl-:qs

' PATENT XoFFlcE v2,111,659 mimmo PUMP 'on Moron Elek Benedek, Bncyrus, hio

l Application s claims.

pumps have the disadvantage of imposing great hydrostatic load on one side-of the valve pintle because the eccentric effects pressure strokes of the pistons atv one side of the barrel only, in other words, is single acting; each piston having one pressure and one suction stroke during each revelution of the rotor. This imposes a great unbalanced hydrostatic load on the hydraulically acting surfaces of the cylinder barrel and great unbalanced mechanical load on the supporting bearings. Another disadvantage of such sec-. ondary rotor arises from the necessity for large supporting bearings for the eccentric mechanism, '-'J Vwhich bearings cannot operate properly at' the necessary high speeds for high volume delivery at comparatively high pressures, due to the great centrifugal forces `imposed on the rolling. elements and associated cages. ""9 The principal object of this invention is the provision of a .hydrostatically balanced variable displacement pump wherein the hydrostatic pressure load is balanced about the valve pintle, and wherein the load imposed on the bearings'of the piston barrel or Aprimary rotor are likewise balanced. v

' Another object of the invention is the elimination of a secondary rotor and necessary large 40 cheaper and more practical construction. for

large pumps and motors.

`A further object is'to reduce the number of moving parts and rotating mass in pumps vor 45 motors of the type above referred to.

' In pumps of prior design, pintle, lubrication is ordinarily effected by the working pressure of the pump, consequently when the pump is running idle, or at low pressure, the pintle is not lubri- ,-,0 cated except at low pressure.

A further lobject of the invention therefore is in 4the provision ,of pressure lubricating means for` the hydrostatically balanced valve in order to 'lubricate the pintle at all times with uid under :.3 high pressure.

A further object is the provision of adjustable fully balanced stationary cam or reactance lmeans to control the stroke of the pistons and the delivery of the pump.

co A further objectl is the provision of a n ovel lanti-friction bearings therefor to provide av 'october4 24, 1934; serial No. 749,746

(ci. 10a-,161i

hydraulic control to operate the adjustable cam .or reactance means of a pump of the class mentioned, to thereby change the stroke of the pistons and the delivery of the pump.

Further objects and advantages will appearv from the following description relating to the accompanying drawings, showing a preferred form.

Referring briefly to the drawings:

Fig. 1 is a longitudinal horizontal-central sectional view of a pump constructed yaccording to `the spirit of this invention;

Fig. 2 is a transverse sectional view of the pump taken on line 2-'2 in Fig. 1, showing the pistons and the vadjustable cam mechanism in its zero stroke position whereby the pistons revolve bodily in a circle but do not reciprocate;

Fig. 3 is a transverse sectional view similar to I that of Fig. 2 with the partslin the same position, taken on lin'e 3-3 in Fig. 1; Fig. 4 is a sectional view similar to Fig. 3 with thefpiston operating rollers omitted and showing the adjustable cam mechanism in vits maximum stroke position;

Fig. 5 is a longitudinal central sectional view at right angles to Fig. 1, taken on line 5-5 in Fig. 2, showing. the pistons in their radially inwardmost position;

Fig` 6 is a transverse sectional view of one of the main pump connections taken on line 6 -6 in Fig. 5;

Fig. '1 is an enlarged detail sectional view of th piston operating yoke and roller assembly according to Figs. l and 5;

Fig. 8 is a fragmentary sectional view of a piston unit assembly showing the connection of one piston with vthe piston operating rollers and also showing the cooperative relationship between the ship of the movableand stationary parts of the piston operating cam mechanism when the cam -parts are in idle position, according to Figs. 2

and 3;

Fig. 11 is a view similar to Fig. 10, showing the cam parts in maximum stroke position thereof Figs. 12 and 13 are detail sectional views taken on lines |2-l'2 and I3--l3 respectively in Fig. 1; Fig. 14 is a longitudinal central sectional view Vf one of two pilot valves of a hydraulic servomechanism of the pump;4

Fig. 15 is a sectional view thereof taken on line |5--I5 in Fig. 14; Fig. 16 shows the clevis connection between one of the pilot valves and associated linkage;

Fig. 17 shows a front elevationof the pump motor designed to actuate the aforesaid cam i equipped with the servo-motor of Fig.

' pistons proper indicated at 28 in the radial cyl- 14, together with the operating toggle mechanism thereof designed to eifect 'simultaneous adjustment of the piston actuating cams;

Fig. 18 shows in sectional plan the lever connections of the toggle mechanism, taken on line l8-l9 in Fig. 17; and

Fig. 19 is a detail section of a modified relief valve.

Referring first to Figs. 1, 2 and 5, the general casing of the machine comprises heavy casing sections I and 2, the section I having a central cylindrical body portion I' and a suitable end wall integral therewith, the end wall carrying a heavy integral hub l for supporting a valve pintie to be hereinafter described. 'I'he casing section 2 is appropriately secured as by a shoulder joint 9 to the cylindrical portion I' of the casing member I completing the casing.

Secured in the hub l is a valve pintie 5 having an enlarged cylindrical portion 5a adapted to be securely fastened as by press fit into the central bore of the hub and a 'reduced portion 5b .extending within the casing and having a working portion 5c hydraulically tted into the central bore of a cylinder block or barrel III, above referred to as the primary rotor. The rotor I8 is preferably a one piece forging and is provided with radial cylinders I I communicating at their inner ends with the central portion I2 of the rotor which, as above stated, is in hydraulic t relation to the working section or portion 5c of the pintie.v

The complementary working surfaces may be slightly tapered and the clearance between the working surfaces is very slight. 'Ihe rotor also has an impeller shaft portion I8 projecting from inders II, the cylinders being preferably formed in a radially extending flange portion 2l of the rotor extending continuously about the rotor in the zone of the pistons. The cylinders I I at their inner ends have reduced inlets Ila adapted for communication withA four equally spaced ports 8 yin the hydraulically tted portion 5c of the pintie. The ports 8 communicate through resp'ective axial passages in the pintle. (not shown) with the radial main inlet and discharge ports 'I in the relatively enlarged portionl 5a of the" pintie. 'I'hese main ports 1 respectively communicate with circular passages 8 and 9 in the casing hubiI which, in turn, communicate with lmain fluid feed and discharge pipes 8a and 9a through suitable connections. 'I'he mains are used interchangeably for admitting and discharging the operating fluid dependingv upon the direction of rotation of the rotor (when used as a Pump e. 8.). To further .insure the free running of the rotor at all times. there is preferably a relief spaceA 2l provided between the' pintle and rotor in theV radial zone of bearing I4, to thus avoid binding of the pintie upon unequal The inner race members expansion and contraction of the rotor and pintie due to heating of the bearing.

It is important to retain the slip fluid which passes the working surfaces of the pintie and rotor from the ports i rather than to allow the escaped fluid to pass freely into the outer'surrounding casing. For this purpe I haveprovided a strong relief valve located in a reduced extension of the central rotor bore. 'Ihis extension provides a iiuid reception chamber 21 communicating with a central vopening 25 in a valve seat member 28. A ball check 29 is pressed tightly against the central opening 25 by a suitable spring 39 bearing at one end in the end of the bore. 'I'he bore portion 26 which contains the spring is provided with radial passages Il leading to the casing space 3|' adjacent the bearing I 3 as shown in Figs. 1 and 12. When the pump e. g. is operated at high pressure the slip fluid escaping from the working surfaces of the rotor and pintie accumulate in the spaces 25 and 26 and when the pressure becomes excessive the excess fluid escapes by lifting the ball 29. The fluid is retained under pressure in the said reception spaces and, whenever the working pressures of the pump become less, then fluid from the reception spaces travels in the reverse direction toward the supported end of the pintie, maintaining lubrication for the working surfaces during such low pressure periods or cycles of the pump. The bearing I3 is supplied with lubricating fluid from the passages 3i and the bearing I4 by fiuid escaping from the working surfaces through relief space 2|.

Fig; 19 shows a modified relief valve which may be used insteadof 'the construction shown in Figs. 1 and 5. The parts that correspond to the relief valve parts of Fig. 5 e. g. are similarly numbered.

In Fig. 19 the ring 28 forming the valve seat member is closely fitted into its counterbore in the rotor but may slide in said counterbore (lap iit e. g.). 'I'he ring 28 at one end abuts a retaining member such as a threaded ring 28a against which the ring 28 is normally held by the spring 30 in its operation of holding the ball 29 in its seat. When pressure builds up in the effective fluid reception chamber 25-21 the fluid, rather than being permitted to escape by lifting the ball', will act on the relatively larger exposed transverse area of the ring 28 forcing the ring and ball to move bodily to the left until the ring abuts the surface 28h of the counterbore, whereupon should the pressureA in the now enlarged but closed reception spaces continue to build up the ball will finally unseat to relieve the pressure into the chamber surrounding the spring 30. The released fluid may, of course, be suitably drained, say as shown in Fig. 5.

Now when the operating pressure of the machine is reduced to such a point that fluid is no longer forced between'.the hydraulically fitted working surfaces of the pintie and rotor toward the impeller shaft end of the rotor the spring vanyzplston stroke setting of the machine, and

said means effects two pressure strokes and two suction strokes of each piston on each complete rotation of the rotor. Thus the hydraulic load scribed.

i rotor in spaced relation,

As shown in Figs. 2, 3 and 5, the cylindrical inner peripheral surfaces of the casing support segmental guide blocks 35, two at each side of one adjacent each flat inner end wall of the casing at respective sides of the rotor.- The chordal surfaces 36 provide four The adjustable cam members 31 parallel guides. ride on these guide blocks, which latter are-suitably secured rigidly to the casing by any convenient means (not shown), the blocks being spaced apart and connected by suitable bars 35 having reduced ends 35 entering openings in respective blocks. The individual cam members 31 are C-shaped and each has outer and innerA .track forming surfaces and 4l respectivelyforming guides for piston rollers e. g. 50 carried Y soon suitable cross head members 5l of the pistons, to be later described.-

The tracks afforded by the cam members 31 when the latter are in abutting relation, asshown in Fig. 3 form a complete true circle coaxial with the rotor andv hence, in this position, impart no reciprocatlon `to the pistons.

.The cam -members 31 are, as shown, four in number, being in pairs on opposite sides of the rotor between the guide blocks 35, the members of each pair bars 38 to which oppositely extending adjustment bars 38 are connected for shifting the cam members 31 equal distances from Yand toward the axis of the rotor as will be later described. The arrn'portions of the C-shaped cam members are slotted as at 42-c-see Figs. 10 and llto straddle straight tongues or ribs 43 rigid on the respective.

blocks 35, the tongues thus serving as rigid right line guides for the cam members 31 during adjustment. Additionally, the inner surfaces of the tongues are made exactly tangential to the outer roller track surfaces 40 so as to bridge these track surfaces as piston roller supports when the C-shaped cam members are spread `apart (as in Fig. 4).

The rollers are, of course, long enough to ex- I tend into contactwith the tongues 43.as well as the track surfaces 40 as shown particularly in Fig. 5. Thus adequate 'continuous outer roller guiding tracks are provided for the piston rollers in all adjustments of the cam members 31; no inner bridging tracks being necessary because the function of the inner tracks is solely to force the pistons outwardly on their'suction strokes, and these strokes always begin vat the position of the rollers shown in Fig. 3, i. e. aligned with both the inner and outer track surfaces. Y

Referringnow to the piston roller supports 5| on the pistons, earlier mentioned, these, in order -to reduce the diameter ofthe cam tracks and thus the peripheral speed of the rollers at any given rotor speed, comprise yokes pinned or otherwise .securely fastened to the' outer ends pistons, each yoke having a pair of arms 52 extending inwardly toward the rotor axis at opposite sides of the central rotor ange, the arms carrying the rollers on laterally extending stub shaft portions 53 of the respective arms. ToYreducertorsionalwstrainon the pistons and yokes the arms of the yokes may be slidably supbeing connected by suitable cross head` ported in radial ways 54 (see Fig. 8) formed vin the central web or ange 2l of the rotor.

An important novel feature of the invention is the provision of needle roller supports for the rollers 50 on the cross head pins such as the stub shafts 52 ofthe yokes. The needles are very small and inexpensive and roll directly on undercut surfaces 55 which afford endwise retaining shoulders 55' for the needle elements. The needles, as shown, roll directly on'the inner substantially cylindrical surfaces of the piston actuating rollers 5|) and the rollers may be confined -by the adjacent surfaces of the cam members 31 in keeping with the provision of a truly hydro- 2 statically and mechanically balanced pump or motor mechanism. To this end I provide servomotors and actuating toggle mechanism shown in Figs. 14 to 18 inclusive.

One of the servo-motors 60 is. shown in section in Fig. 14, the servo-motors comprisingV double acting piston heads 6I (one being shown) in 'suitable cylindersv 62, the operating rods of the heads extending into the main pump or motor housing through respective aligned openings 64 in thecylindrical central portion of the casing part l, the rods being, in fact, the control rods 38', earlier described, which connect through suitable crossheadswith the cam members 31.

The cylinders 62 are, as shown, one piece castings appropriately secured as by cap screws 65 to the pump 'or motor casing in sealed relation thereto. The chambers 10 and 1I at the opposite ends of thepiston head 6l are fluid tight. `A pilot valve 12 slides in a central bore 13 of each piston head and the `operating stems 12' of the pilot valves extend from respective 'outer cylinder ends through suitable packing gland assemblies 14 (Fig. 14) to the operating toggle mechanism as shown in Fig. 17.

Centrally of the cylinder 62 operating uid is fed to the cylinder underpressure through apin the piston head as shown in Fig. 14 and from thence the fluid passes through passages indicated diagrammatically at I'Ito a long peripheral channel 18 formed on the pilot valve. The cylindricalportions 19 andv 88 of the pilot valve normally close radial passages 8l and '82 in the piston Ahead ighich respectively communicate with axial -bores I and 82' in the head leading to respective chambers'lll and 1 I so as to convey the operating uid to one or the other of said chamber depending on the setting of the pilot valve.

It will be seen that wheneverthe pilot valve is shifted toward the right (Fig. 14) luid will be passed tothe chamber-III from 18 to 82 through passages 82, and the head will be moved to the the chamberlll will be cut off .by reason of the portions 12 ofthe valve blocking the passages 82.. vDuring'the time the head'has beenso moved to the right the fluid remaining ln the chamber--15 'll is vented to a central bore 85 of the valve by reason of cross-passages 86 (see Fig. 15) which, during the time the chamber 10 is being supplied, register with one of the passages 8l of the head. 'I'he servo-motor operates in exactly the reverse manner when the pilot valve is moved to the left (Fig. 14) except that the cross-passage 86 are then communicated directly with the chamber 10 to relieve the same as will be apparent from the drawings. The iiuid discharged from the bore .85 may be conducted into the general pump casing I-2 etc. from which it may be suitably drained as through an opening 88, Fig. 3, in the bottom of the casing.

To operate the pilot valves from a common point and thus assure the accurate setting of the cams 3 1 equal distances from the rotor axis, I provide levers Sil-Fig. 1'7-pivoted on swingable links 9i, the lower ends of which levers are attached as by suitable clevis-pivots 92, see also Fig. 16, to the outer ends of the pilot valve stems l2. The levers 90 extend upwardly to toggle links 8l pivotally secured to the levers and which are plvotally secured to each other as by a pin 95 (Figs. 17 and 18) and to an operating head 96 in the nature of a fork slidably mounted in a lvertical guide block 91 surmounting the machine.

The position of the levers and toggle links illustrated in Fig.17 corresponds to the neutral setting of the machine wherein the pistons revolve idly but do not reciprocate. When the operating head is shifted from the illustrated position either up or down the upper ends of the levers 90 will be brought toward each other and the pilot valves withdrawn with respect to the cylinders B2, thus causing the servo-motors to correspondingly move the c'am members 31 away fromthe rotor aids.

The great advantage of hydrostatically balancing the valve and cylinder mechanism whereby the valve is under no strain and consequently can be mounted floatingly in the casing, so as to iind its own ways in the cylinder block bore without any strain, will be appreciated from the above description. In pumps of the hydrostatically unbalanced type the valve is always under a strain and one sided pressure, therefore a very rigid mounting in the casing is necessary for such valves and even with such very rigid mounting, operation is very often accompanied by rubbing, due either to mis-alignment or deformation of the parts under load. These faults are entirely eliminated from the present design and consequently greater safety factors and longer useful life are accomplished -and obtained. main advantage of this structure is the elimination of large antifriction bearings and the substitution of capillary needle bearings for the rolling elements which are operated by the stationary cams.

It will be seen that by a 90 rotation of the cam mechanism, in either direction relative to. 'the pintie, the delivery oi the machine acting as a pump may be reversed, or the rotation as a V motor may be reversed. 'Ihus all the advantages.

Aol' a single acting unbalanced type variable delivery pump are not only available in this design but, due to the fact that great hydrostatic pressures are balanced and thus great mechanical loads are eliminated for heavy duty service, and emcient service and durability are assured.

I claim:

1. In a hydraulic pump'or motorof the rotary .'radial plunger type,inc1uding a casing, a rotatable barrel. and a plurality of plungers carried Another said reactance track portions defining an arcuate continuous track when the elements are adjusted to their innermost positions, and means to move said elements concurrently toward and awayfrom each other while maintaining the elements in symmetrical relation with respect to the axis of rotation and for retaining the elements in said adjusted positions, said means comprising a pair 'of hydraulic mechanisms, said mechanisms being directly rigidly connected to the casing and each having an operating plunger, said plungers being diametrically opposite to each other and axially aligned with each other and connected directly one to each of said elements, and said mechanisms being connected in parallel relation to each other in a fluid pressure circuit, a common control mechanism for eiiectingv simultaneous connection and disconnection of said mechanisms in said circuit, whereby the movement of each of said elements and the reactance resistance aiforded by each is equalized.

2. In a hydraulic pump or motor of the rotary radial plunger type, including a casing, a rotatable barrel, and a plurality of plungers carried thereby, adjustable reactance means for the plungers and providing a continuous reactance track for the plungers in all adjusted positions of said means, said means including a pair of reactance elements having arcuate symmetrical reactance track portions and being arranged diametrically opposite to each other and movable toward and away from the ,axis of rotation of the barrel,'said reactance track portions dening an arcuate continuous track coaxial with the barrel whenthe elements are adjusted to their innermost position, means to move said elements concurrently toward and away from each other while maintaining the elements with the track portions in symmetrical relation with respect to the axis of rotation and for retaining 'the elements in said adjusted positions, said means including a pair of equal size pilot controlled follow-uphydraulic servo-motor mechanisms, said mechanisms being directly rigidly connected to the casing diametrically opposite to each other and each having an operating plunger, said plungers being diametrically opposite to each other and axially aligned to each other and being directly connected .one to each of said elements, and said mechanisms being connected in parallel in a pressure iluid circuit, a common control means for the said mechanisms for effecting corresponding equal operations thereof concurrently in either direction whereby the reactance forcesvon said. elements are hydraulically baly anced.

3. In a hydraulic pump or motor ot the rotary.'

rotation of the rotor and symmetrical with respectto each other, said reactance elements being adjustable relatively toward and away from' l annoso each other to dierent positions for varying the stroke Iof the assemblies, means in the casing supporting said reactance elements with their axes parallel to the axis of rotation of the rotor and 'for movement parallel to a xed plane main operating reciprocable piston, said mechanisms being rigidly 4connected to diametrically opposite sides of the casing with the main pistons thereof axially aligned with respect to each other and the axes of the pistons lying in said fixed plane and extending at right angles to the axis of rotation of the rotor, rigidv rods coaxialA with the said main pistons of said mechanisms respectively and directly connected to said reactance elements respectively at diametrically opposite sides of the axis of rotation, said mechanisms being connected in a common fluid circuit and a common control means .for the pilots of said mechanisms for effecting concurrent operations thereof to effect, in turn, concurrent operation of the main'pistons thereof.

4. In a'hydraulic pump or motor ofthe rotary radial plunger type including a casing, a rotor mounted therein, plunger and cylinder assemblies carried by the rotor, valve means for the assemblies, reactance means for the assemblies within said casing, and including arcuate reactance track elements arranged diametrically opposite each other with respectto the axis of rotation of the rotor and symmetrical with respect to each other, said reactance elements' being adjustable relatively toward and away from each other to different positions for varying the stroke of the assemblies, means in the casing supporting said reactance elements with their axes parallel to the axis of rotation of the rotor and for move-A ment parallel. to a xed plane through the axis of rotation of the rotor into different adjusted positions, means to move said reactance elements to said adjustedpositions, said last named means including a pair of pilot plunger controlled follow-up hydraulic servo-motor mechanisms, each mechanism including a main-operating recipronected to diametrically opposite sides of the casing with the main pistons thereof axially `aligned with respect to each other and the axes of the pistons lying'in said xed planeand extending at rightangles to the` axis Aof rotation of the rotor, rigid rods coaxial with the said main pistons'of said mechanisms respectively and d lrectly connected to said vreactance elements respectively at diametrically opposite sides of the .axis of rotation, said -mechanisms being connected. in acommon uid circuit, a common control means jfor the pilots of said mechanisms for eifecting concurrent operations thereof to eiect;

in turn, concurrent operation of the main pistons thereof, said common` control means inclu g a main control rod and balanced toggle connections betweenA the main control rod and the pilots of said mechanisms for causing opera- 'A Y i tion of said pilots in unison with each other.

5. In a hydraulic pump or motor of the rotary radial plunger type including a rigid casing, a rotor mounted therein, plunger and cylinder assemblies carried by the rotor, valve means for the assemblies, adjustable reactance means for thev assemblies including a pair of separable elefments having curved operating track portions,

the rotor and parallel to said axis of rotation, l

means to move -saidelements toward and away from each other to diiferent adjusted positions while Vmaintaining the same with their track portions in said symmetrical relation, said means including a pair of vequal sized pilot controlled, follow-up, hydraulic, double-acting servo-motor mechanisms, jeach mechanism including a main operating reciprocating piston, said mechanisms being connected to the casing with their respective pistons axially aligned and with the axis of each piston lying in said xed plane and extending at-right angles to the axis of rotation, rigid rods coaxial with the pistons of said mechanisms respectively and directly connected to said elements respectively for transmitting forces directly between said elements and associated pistons, said pistons being connected to the elements at diametrically opposite sides of the axis of ro tation, said mechanisms being connected in parallel in a uid circuit, and a common control means for said mechanisms for effecting equal -operations thereof concurrently in opposite directions, whereby the reactance forces on said reactance means are balanced by the pistons of said mechanismsV at all times and are equal and opposite with respect to each other.

6. In a pump or motor of the character described, a casing; a rotor rotatably mounted in the casing; radiating, co-planar piston and cylinder assemblies carried by the rotor; valve means therefor; reactance means surrounding the rotor and supported in the casing, said reactance means including a pair of .adjustable separable cable piston, said mechanisms being rigidly'conl load track members movable toward and away metrically disposed with respect to the axis of rotation of the rotor; connecting outer load track meansV associatedV with the outer trackways o f said members and forming therewith ka. continu' ous outer workingcontour'in all adjusted posi.

of the respective load track members being symtions of vsaid members; and thrust-transmitting members respectively projecting laterally .from

the outer ends of said assemblies, and into .thev grooves in said load track members, and beingl in operative association with both the outer and the inner trackways of said members.

ELEK K. BENEDEK.

so from each other, each load track member having 

